Günter Ege

Zur Konjugation in makrocyclischen Bindungssystemen [1]

A simple formula (14) has been derived for the calculation of the perturbed first order orbitals, which is applicable to systems with degenerate unperturbed eigenvalues. With formula (14) it is possible to calculate second order energy-derivatives like chemical shifts or magnetic susceptibilities for systems with degenerate eigenvalues without any extrapolations. This formula has been applied to the calculation of 1H-chemical shifts of Circumpolyacenes, which have degenerate HMO- and SCF-eigenvalues.

Zur Konjugation in Macrocyclischen Bindungssystemen—VI : SCF-mo-berechnung der bindungsabstände in makrocyclischen bindungssystemen

Zusammenfassung SCF-Berechnungen ergaben fur die makrocyclischen Bindungssysteme I bis VI starke Bindungslangenunterschiede entlang der Peripherie. Auf Grund dieser Ergebnisse konnen diese Systeme daher nicht als makrocyclische Annuelene aufgefasst werden.

Simple MO-calculations of the charge-transfer absorption in quinhydrones

Abstract HMO-calculations of charge-transfer absorptions are reported for the “pseudoortho” and “pseudogeminal” orientations of 1,4-benzoquinone and hydroquinone. This approach is used to explain the difference in the charge-transfer absorptions which have been observed for the corresponding intramolecular quinhydrones 1 and 2.

[7+2]- and [11+2]-cycloaddition reactions of diazo-azoles with isocyanates to azolo[5,1-d] [1,2,3,5] tetrazine-4-ones

Abstract Diazo-azoles react as 1,7- or 1,11-dipoles with isocyanates to form the hitherto unknown pyrazolo[5,1-d] [1,2,3,5]tetrazine-4-ones, [1,2,3,5]tetrazino[5,4-b]indazole-4-ones and [1,2,3]triazolo[5,1-d][1,2,3,5]tetrazine-4-ones in a [7+2]- or [11+2]-cycloaddition reaction.

Simple MO calculations of the zero-field splitting parameters of cyclophanes

Simple MO theory is used to calculate the zero-field splitting parameter D of the lowest triplet state of double and triple-layered cyclophanes. Our approach explains the differences in the D values of diastereomeric intramolecular charge-transfer systems and the differences between phanes with identical aromatic units and those consisting of a donor and an acceptor.

[7+1]- and [11+1]-Cycloreactions of diazo-azoles with 1-nucleophile-1-electrophiles (ylides) to 3H-pyrazolo[5,1-c][1,2,4]triazoles and 3H-[1,2,4]triazolo[4,3-b]indazoles

Zusammenfassung Diazo-azoles react as 1,7- or 1,11-dipoles with ylides such as diazo-alkanes or such of the phosphonium-, sulfonium0, pyridinium- and sulfene-type to form 3H-pyrazolo[5,1-c][1,2,4]triazoles and 3H-[1,2,4]-triazolo[4,3-b]indazoles in a [7+1]- or [11+1]-cycloreaction.

Conjugation in macrocyclic bond systems—VI : 1H-chemical shifts of annelated annulenes

Abstract The nonlocal contribution of the pi-electrons to the 1 H-chemical shifts in the annulenoid systems 1–12 is calculated within the HMO theory from which information is gained about the change of the annulenoid character of (4n) and (4n + 2)-annulenes by different annelated groups. The predicted trends are then compared with experimental data. Calculated ground state stabilization energies and aromaticity indices based on the uniformization of bond lengths show no correlation with the chemical shifts.

Skelettumlagerungen unter elektronenbeschuss—III : Benzotriazinone und 1,3-diphenyltriazene

Zusammenfassung Durch Appearance-Potential-Messungen wird fur das Produkt der primaren Stickstoffabspaltung aus 3-Phenyl-naphthotriazinon eine Vierringstruktur ausgeschlossen. Die Fragmentierung einiger 3-Phenyl-benzotriazinone und vergleichbarer 1,3-Diphenyltriazene wird durch hochaufgeloste Messungen und 15N-Markierung untersucht Die Methanoleliminierung aus orthosubstituierten Benzoesauremethylestern ist uber Sechs- und Siebenring moglich.

[3+2]-cycloreactions of 1,2-diacylcyclopropenes with ynamines. Aminofurane- versus aminocyclopentadiene-formation

Abstract Electron deficient 1,2-diacylcyclopropenes represent synthetic equivalent for both acylcarbenes and vinylcarbenes; in their cycloreaction with ynamines aminofuranes and/or aminocyclopentadienes are formed.

Photochemically induced [4+2]- versus [3+2]-cycloreversion reaction of hexasubstituted 2,3-diaza-bicyclo[3.1.0]hex-2-enes☆

Abstract Hexasubstituted 2,3-diaza-bicyclo[3.1.0]hex-2-enes containing large substituents at C-4 and C-6 upon irradiation undergo a novel [4+2]cycloreversion reaction leading to 2,3-diazahexatriens besides the normal [3+2]cycloreversion.